Approximately 30 billion pounds of cheese whey is produced every year. Of this amount, about one-third is utilized as human or animal feed in some form. The remaining whey is both a serious pollution problem, and at the same time a challenge for profitable utilization. Present processing of whey includes simple drying of the whey to a powder containing all of the original solids, the use of reverse osmosis, ultra filtration, gel fractionation, and electrodialysis, which result in varying degrees of fractionation and purification of the whey protein. While the raw material is cheap, these processes add substantially to the cost, generally resulting in a price that is not attractive or competitive with a conventional source of protein. Existing methods appear to be attractive only for: 1 large operations where the whey is available on sight, 2 captive use of the finished product, or 3 preparation of special, or high purity products for which a known market exists. It is known that transportation costs are generally limiting for raw whey and that the use of conventional concentration equipment, for the purpose of reducing the weight to be hauled, is not economically feasible for the small dairy operation.
Various processes have been developed for the separation of protein from whey. U.S. Pat. No. 2,519,606 discloses a process of recovering protein from aqueous liquid material containing protein in coagulable form. A gas is injected into the liquid to form a foam, the bubbles of which carry up adherant coagulated protein particles. The protein isolated in this manner is therefore separated by gravity. U.S. Pat. No. 3,252,961 issued May 24, 1966 discloses a process for separating whey proteins involving the flocculation of the proteins as an easily separable curd after denaturation by heat and precipitation under specified conditions. This flocculation method employs special flocculating agents. The curd which forms and comprising the flocculated protein is then separated from the liquid and collected by any suitable method. Both methods disclosed in these patents however, are concerned with the separation of insoluble proteins and are similar consequently, to ore froth flotation wherein the insoluble particles are carried off by a foam. Such processes cannot be employed to separate the soluble proteins, such as lactalbumin and globulin, from whey in a soluble and essentially undenatured form. It is in this form that the protein has its greatest utility for incorporation into food products.